Once the dialog is dismissed, focus is not transferred directly to the immediate
or previous object (in this case it's element) and focus is lost even though the
element is still displayed as it's selected. So, can't get back to the last
selected element for bringing up the dialog.

Repro steps:
- create a class diagram
- create and name a class element
- right click on the class element and select Edit->Set Dimensions...
- press Cancel or Ok button to dismiss the dialog
Result: no idea where the focus is now so keyboard access to the diagram is no
longer possible.